Cleavage of human PAR-2 peptide by serine proteases. A peptide corresponding to region surrounding the cleavage site of human PAR-2 (³²SSKGRSLIGKVDGT⁴⁵) was incubated with the serine proteases PR3, HLE, and CG, and proteolytic fragments were analyzed by reverse chromatography, N-terminal sequencing, and mass spectrometry. The cleavage product of PR3 ended with a valine residue at position 42 (V⁴²-D⁴³), CG cleaved between lysine and valine (K⁴¹-V⁴²), and HLE between isoleucine and glycine (I³⁹-G⁴⁰). Trypsin, a known activator of PAR-2, was used as a positive control.